Lifting jack



L. T. JOHNSON.

LIFTING JACK.

APPLICANON MED :v1/m23, x92..

Pafand; June 6, i922.,

1&1951..

3 SHEETS-SHEET 3.

-. T. JOHNSON.

LIFTING JACK.

APPLICATEON FILED MAR-723,192.

Panw June 69 1922,

3 SHEETS-SHEET 2.

L. T. JOHNSON.

LIFTING JACK. y APPucATeoN FILED MAIL-23, 1921.

Patented June 6, 1922.

3 SHEETS-SHEET l.

LWRENCE T. JOHNSON, 0F BUFFALO, NEW YGRK.

LIFTING JACK.

Application filed March 23, 1921.

To (1N 'zc/2.0m it may concern Be it known that l. LAWRENCE T. JOHN-soN. a citizen of the [Ynited States, residing in Buffalo. in the countyof Erie and State of New York, have invented new and useful Improvementsin Lifting Jacks, of which the.- following is a specification.

This invention relates to a hydro-pneumatic lifting jack and hasfor itsmain object the production of a lifting jack of this character which isa unitary structure, which is compact and capable of being readilytransported, and which can be easily operated for raising and loweringvery heavy loads such as railroad cars and the like when the samerequire repairing and for other purposes.

In the accompanying drawings: Figure lis a side elevation of thepreferred embodiment of my invention. Figure 2 is atop plan viewthereof, partly in section. Figure 3 isa vertical longitudinal sectionof the lifting jack. Figure 4 is a fragmentary vertical transversesection taken on line 4 4, Fig. 3. Figure 5 is a fragmentary verticallongitudinal section of the air controlling` valve mechanism similar tothat shown in Fig. 3, but in a different position. Figure 6 is a viewsimilar to Fig. 4 but .showing its arts in a different position. Figure7 is a horizontal section taken on line 7 7, Fig. 3. Figure 8 is ahorizontal section taken on line 8 8, Fig. 4. Figure 9 is a fragmentarysectional perspective view of the air controlling valve mechanism.Similar characters of reference refer to like parts throughout theseveral views.

The main supports of this lifting jack lmay be variously constructed butas shown in the drawings the same preferably consist of a lower base 10of metal which rests horizontally on the ground or floor when in itsoperative position. On the front endof this base is arranged an uprighthydraulic lifting or hoisting cylinder 11 which may be secured at itslower end to the base in any suitable 'mannen Within this liftingcylinder is arranged a vertically movable lifting or hoisting piston orplunger 12 provided at its upper end with a lifting head 13 which isadapted to engage with the load to be raised. The raising of the liftingpiston and the load carried therebyv is effected by introducing a liquidsuch as water or oil into the lower end of the lifting cylinder so thatthe hydraulic pressure raises the lifting Specication of Letters Patent.

Patented J une 6, 1922.

Serial No. 454,749.

piston and upon discharging the liquid from the lifting cylinder theVpiston therein rand the load supported by the same will be lowered bygravity. Upon the rear part of the base are mounted the means wherebythe pressure liquid is supplied to the lifting cvlinder.. these means intheir preferred form being constructed as follows:

14 represents an upright cylindrical wall which is secured at its lowerend to the rear partof the base so that. the latter forms a closure orhead for the lowerend of the same while the upper end of the same isclosed by a partition 15. The spacel within the lower part of thechamber forms a liquid supply tank 1G and the space within-the upperpart thereof forms the kmotoricvlinder 17 of an auxiliary motor which ispreferably operated pneumatically. Centrally within the 'liquid tank isarranged an upright pressure pump cylinder 18 whichy has its lower lendrigidly mounted on the base and placed in communication with the lowerpart of the liquid supply tank by an inlet passage 19 and also connectedwith the lower end of the lifting chamber by an outlet passage 20.Liquid is permitted to iiow only from the tank to the pressure cylinderthrough the inlet conduit 19 but prevented from moving in a. reversedirection by a check valve 21 in this passage and similarly liquid isonlv permitted to flow from -the pressure cylinder through the outletconduit and to the lifting cylinder but held against a return movementtherein by a check valve 22. which check valves may be of any suitableconstruction although those shown in Fig. 3 of the drawings are of thespring operated type. The liquid is drawn from the tank into thepressure lcylinder' and expelled therefrom into the lifting cylinder bya. pressure pump piston or `plunger 23 which reciprocates within 'thevpressure cylinder. Liquid may be .sup-

plied to the tank through one or more filler and vent openings 24 in thewall 14, one at the parts being so proportioned that a plurality ofreciprocations of the pump piston are necessary to elevate the hoistingpiston its' fullest extent. When it is desired to again lower the pistonof the hoist the liquid is discharged from the latter and preferablyreturned to the tank so that it can be used repeatedly by an opening orvalve 26 in a This piston is depressed for causing the pressure. pistonto expel the liquid from the pressure cylinder of the pumpl into kthchoisting cylinder by introducing compressed" air into the auxiliarymotor cylinder through a port 29 in the wall of cylinder 17. Theauxiliary motor only operates to assist in depressing the pump piston,an additional main pneumatic motor being provided which preferablyoperates in conjunction with the l auxiliary motor to depress the pumppiston partition.

but acts solely to raise the latter. This main motoricomprlses a mainmotor cylinder 3() mounted-on top of the auxiliary cylinder and havingits upper end closed by a head or cover 81. For the sake of greaterstability this upper head is connected with the upper end of thehoisting cylinder byv a bracket 32 as shown in Figs. l, 2 and 3. Thepartition 15 is preferably interposed between the auxiliary and maincylinders and serves as heads for the opposing ends of the same. Tithinthe main cylinder is arranged a main motor piston 33 which is connected'with the auxiliary motor piston and the pump piston by a connecting rod34l passing through a stuffing hox35 arranged. on the inder throughports 36, 37 foijthe purpose of depressing and raising the main motorpiston, and these ports are alternately connected '.with an exhaust port38 leading to the atmosphere for the purpose of carrying away thel spentpressure tluid from either side of the main motor piston while theopposite side thereof is subjected to the action of the live pressurefluid. The port 29 in the upper end of the auxiliary motor is connectedby a pipe or conduit 39 with the upper end of the main motor cylinder sothat the pressure medium is simultaneously supplied to and exhaustedfrom the upper Compressed air is supplied to upper and lower ends of themain motor cyl-y ends of the auxiliary and main motor cyl inders.

Various air controlling valve mechanisms may be employed, that shown inthe drawings being actuated automatically by motion derived from themotor pistons and constructed as follows:

40 represents a main valve chamber connected by a pipe 41 with acompressed air ends ot' thermain and auxiliary motor cylinders fordepressing theplston's therein and forcing the pump plunger downwardly,while the spent air below the main motor piston is permitted to escapethrough the exhaust. This main air valve 42 is actuated ,I p

by means of two pistons 44, 45 of different areas reciprocating incylinders 46, 47 at opposite ends of the valve chamber and connectedwith'eacli other and with the main slide valve 42 bya shifting rod 48.The outer end of the small piston cylinder 46 in which thesmallshiftingy piston movesis connected constantly with the outeratmosphere through an exhaust port 49. 50 represents -a verticallyslidable auxiliary air valve arranged in a vertical auxiliary valvechamber 51 which is constantly in communi cation with the main slidevalve chamber by a passage 52. The auxiliary slide valve is providedIwith a cavity 53 whereby compressed air from the main valve chamberbetween the pistons therein is either admitted to the outer end of thecylinder 47 containing the large valve shifting piston 45 or thecompressed air is cut off from the same and instead connected with ltheexhaust leading to the atmosphere. When air is admitted to the outerend'of the cylinder 47" the piston 45 is moved toward the center ofV thevalve chamber 40, as shown in Fig. 5, whereby the main air valve 42 isshifted so as to admit compressed air to the upper sides of the main andauxiliary motor pistons and exhaust the air from the underside of themain motor piston. When cutting off the compressed air from the outerend of the cylinder 47 and connecting the same through the exhaust withthe atmosphere the pressure of the air within the main valvecham;

ber 40 being greater against the large piston 45 than against the smallpiston 44will cause the large plston to move away from t the center ofthe main` valve chamber and iliary motor pistons.

of the upward movement of lthe main and tion shown vin F ig.v 3, wherebythe compressed air is 'admitted to the underside of the main motorpiston and exhausted from the upper sides of the main and auxiliarymotor pistons. The supply of the compressed air to and the exhausting ofthe spent air frornthe outer end .of the cylinder is effected by themovement of the auxiliary slide which when elevated, as shown in Fig. 6,permits compressed air to pass from the auxiliary valve chamber throughthe port 54 to the outer end ofthe large cylinder 47 while in Fig. 9 theauxiliary slide valve'is shown in its lowered position in which the port54 is covered and compressed air is cut off from the outer end of the.cylinder 47 and instead the cavity 53 connects a branch exhaust passage55 leading to the outer end of the cylinder 47 with a branch exhaustpassage 56 leading to the main exhaust 38.

The shifting of the auxiliaryV slide valve is effected by a verticallysliding shipper rod 57 which is connected with the auxiliary slide valveand is provided with upper and lower tappets 58, 59, which are adaptedto be engaged by upper and lower shoulders 60, 61 on the motor pistonrod 34. During the main part of the upward movement of the motor pistonsthe ship-per rod'57 and the auxiliary air slide valve remain in theirdepressed position, as shown in Fig. 9, which causes the compressed airto be admitted un- Vder the main motor pistonI and exhausted from theupper sidesofthe main and aux- During the last part l4, and whencompleting this upward movement the auxiliary slide valve has been fullyraised, as shown in Fig. 6, so that now compressed air is admitted tothe outer end of the cylinder 47 and the main slide valve. is shifted soas to cause compressed air to bear down on the main and auxiliary motorpistons and spent air to be exhausted from underneath the main motorpiston. The rod 34 now travels downwardly independently of the shipperrod 57 until it is about to effectl the last part of its' stroke in thatdirection whenthe lower shoulder 61 of the rod 34 engages the lowertappet 59 and draws the same together with the auxiliary air slidevalve. downwardly into a position to again reverse the air connectionswhich will reverse the main slide valve and cause the main and auxiliarymotor pistons to again ascend.

For convenience in transporting the lift ing jack the same is providedwith a. pair of supporting wheels 62 which are so mounted on the lowerrear part of the base that when the latter rests on the ground thewheels will be raised therefrom, as shown in Fig. 3, and thereby enablethe lifting -jack to rest with itsfull weight on the ground for holdingthe same in place. "hen, however, the lifting. jack is to be transportedthe same is tilted backwardly until its weight rests on the wheels 62after which the same may be trundled around with ease to wherever thesame is required. To facilitate handling of the lifting jack at thistime, a transporting pole or bar 63 is provided which is detachablyseated at its rear end in sockets 64, 65 on the motor cylinders andlprovided at its front end with a handle 66.

I claim as my invention: Y

1. A lifting jack comprising a base, a hydraulic lifting cylindermounted on said base. a lifting piston arranged in said cvlinder,ahydraulic pressure cylinder mounted on said base and connected withsaid lifting cylinder, a pressure piston arranged in said pressurecylinder, a pneumatic motor for operating said pressure piston andmounted on said base and' an automatically operating valve mechanism forcausing said pneumatic motor to operate continuously at will.

2. A lifting jack comprising a lifting cylinder, a lifting pistonarranged in said lifting' cylinder, a combination chamber one end` ofwhich forms a. liquid supply tank and the other an auxiliary motorcylinder, a hydraulic pressure cylinder having an `inlet communicatingwith said. supply tank and an outlet communicating with 'said liftingcylinder, a pressure piston arranged in said pressure cylinder, anauxiliary motor piston arranged in said auxiliary motor cylinder andconnected with said pressure piston, a `main motor cylinder, and a mainmotor piston arranged within said main Inotor cylinder and connectedwith said auxiliary motor piston.

3. A lifting jack comprising a lifting cylinder, a lifting pistonarranged in said lift'- end of which forms a liquid supply tank and theother an auxiliary motor cylinder, a hydraulic pressure cylinder havingan inlet communicating with sai/dsupply tank1 and pressure fluid to andexhausting the same from said auxiliary motor cylinder and from oppositeendsl of said main motor cylinder. l f

4. A lifting jack comprising a base, an

'ing cylinder, a combination chamber one.,

upright lifting cylinder mounted on one part of said base, a liftingpiston arranged in said lifting cylinder, a combination chamber mountedon another part of said base and having its lower part forming a liquidsupply tank and its upper part forming an auxiliary motor cylinder, amain motor cyllinder mounted on top of the auxiliary motor cylinder,said auxiliary and main motor cylinders being separated by a partition,a pressure cylinder arranged Within said tank and connected by a valvedinlet conduit with said tank and by a Valved outlet conduit with saidlifting cylinder, a pressure piston arranged in said pressure cylinder,an. auxiliaryxnot'or piston arranged in said auxiliary motor cylinderand connected with said pressure piston, a main motor piston arranged insaid main motor cylinder, a rod connecting'said auxiliary and main motorpistons, and a stu'ing box which is arranged on said partition andthrough which passes said rod.

5. A' lifting jack comprising a base, an upright lifting cylindermounted on' -one part of said'base, a lifting piston arranged in saidlifting cylinder, a combination chamber mounted on another part of saidbase and having its lower part forming a liquid supply tank and itsupper part forming an auxiliary motor cylinder, a main motor cylindermounted on top of the auxiliary motor cylinder, said auxiliary and mainmotor cylinders being separated by a artitio'n, a pressure cylinderarranged Witlun said tank and connected by a valved inlet conduit withsaid tank and by a valved outlet conduit with said lifting cylinder, apressure piston arranged in said pressure cylinder, an auxiliary motor'piston arranged in said auxiliary motor cylinder and connected withsaid pressure piston, a main motor piston arranged in said main motorcylinder, a rod connectingr said auxiliary and main motor pistons, astuffing box which is arranged. on said partition and through whichpasses said rod, and a valve mechanism actuated by motion derived fromsaid motor pistons and operating to admit pressure fluid into andexhaustin the same from said auxiliary motor cy lnder and opposite endsof said main motor cylinder.

LAWRENCE T. JOHNSON.

